Piston expander



Dec. 3, l1940. W C KNOEBEL 2,223,787

PI STON EXPANDER Filed Jan. 6, 1940 FIG l 3 Q W I 7/ NLS I N vE/vroRWALTER C. KNOEBEL PatentedV Dec. 3, 1940 PISTON EXPANDER Walter C.Knoebel, Kirkwood, Mo., assignor to McQuay-Norris Manufacturing Company,St. Louis, Mo., a. corporation of Delaware Application January 6, 1940,Serial No. 312,764

8 Claims.

My invention relates to piston expanders and more particularly to pistonexpanders for use in split pistons of internal combustion engines orvother devices wherein it is desirable to have the 5 expander adjustableso that the expansive force created thereby to open up the skirt andincrease the effective diameter of the piston may be controlleddefinitely.

Heretofore, such expanders have been made in l various shapes and sizesand different expedients have been used to provide adjustability. Theobjects of my invention are to provide an expander of the type describedabove which will expand effectively the skirt of a worn piston and llassure efficient operation of an engine in which the piston is used; toprovide an expander arranged whereby the expansive force exerted therebycan be regulated and controlled; and to provide an expander which issimple in design,

20 heap in manufacture and eflicacious in operaion.

In the accompanying drawing wherein similar characters arer used to.ldesignate similar parts, I have shown one embodiment of my invention.

85 In the drawing, Fig. 1 is a longitudinal section through a pistonincluding my device; Fig. 2 is `a bottom View of the assembled pistonand expander; Fig. 3 is a section along the line 3 3 in Fig. 1; Fig. 4is Va transverse section along 80 the line 4 4 in Fig. 1; Fig. 5 showsthe expander removed from the piston; and Fig. 6 is a section alongandis indicated by the line 6-6 in Fig. 5.

Referring to the gures, the piston shown as including my invention has ahead A including a 35 ring belt B provided with a plurality of ringreceiving'grooves C and a skirt D separated from the head throughoutthemajor portion of its periphery bycircumferentially extending slots E.In order to give resiliency to the skirt B,

0 preferably, it is split longitudinally as at the slot F. 'I'he pistonalso includes the usual bosses G to receive a wrist pin H upon which ismounted the'upperend of the connecting rod J.

The expandershown and described herein as embodying my inventionincludes a plurality oi spring members K formed of spring Wire in thisembodiment. These spring members are arranged inA pairs with the membersin each pair crossing-one anotherv and extending across the BQ hollowinterior of the piston, as shown in Fig. 1. The upper ends of the springmembers K are anchored to the piston, preferably in the head thereof,and the lower or free ends of the members K are adapted to engage andexert an exi# pansive force outwardly against the piston skirt whenadjusted, as explained below. In this embodiment, parts L arranged toengage and bear against the inner surface of the piston skirt atsubstantially diametrically opposed points are fixed to the lower orfree ends of the members K in adjacent pairs.

Extending through each skirt engaging part L is a rod M which isthreaded at its lower end to receive an adjusting nut N and which has ayoke P formed on its upper end. The yoke P may be integral with the rodM or may be secured thereto by any suitable expedient. In thisembodiment each yoke P is provided with holes Q to receive the anchoredor iixed ends of the spring members K, for the purposes to be outlinedbelow, and, preferably, the spring members K have iiattened portions Ror are otherwise arranged whereby the passage of the ends of the springmembers through the yokes will be limited and these ends prevented fromextending more than a short distance beyond the outer side of a yoke.Preferably, the yokes P are formed arcuate in shape to t the roundedinner side of the piston wall when the expander is mounted in place aswill be hereinafter fully explained.

The ends of the spring members K may be secured to the skirt engagingparts L in any way but in this embodiment and as shown in Fig. 6 thefree ends of the members K are reduced asv at S to form a shoulderremoved from the end thereof and the parts L are drilled to receive thereduced ends beyond the shoulder. After the expander is assembled asshown in Fig. the outer ends of these reduced portions are expanded asby hammering and each part L will be carried by the free ends ofadjacent spring members K.

'Ihe manner of installation and operation of thisl form of expanderembodying my invention is as follows: The expander is assembled into theform shown in Fig. 5 and the nuts N are turned into a position at theend of the rods M. The upper ends of the spring members K are insertedin and through the holes Q in the yoke P and the expander is then slidupwardly into the hollow interior of the piston from the bottom thereof.Of course, the connecting rod and piston pin must be removed before theexpander is inserted in place in the piston and preferably the expanderis placed in the piston so that the parts L engage the skirt at pointsremoved approximately ninety (90) degrees from the pin bosses. Asexplained above, preferably, the expander has the upper ends of thespring members anchored in the piston head and to accomplish thi-s twopairs of holes T are drilled in the bottom of a piston ring groove Cwith the holes in one pair being opposed to the holes in the other pair,as shown in Fig. 4. The holes in each pair are positioned to registerwith the ends of the spring members K projecting outwardly from theyokes P and as the expander is slid upwardly in the piston these ends ofthe spring members will enter the holes T and each yoke P will bearagainst the inner side of the wall of the piston head A. After theexpander is in place in the piston the nuts N are turned by a wrench orother tool to move the skirt engaging parts and the free ends of thespring members K upwardly and closer to the anchored ends of the springmembers. Obviously, as such upward movement is continued the free endsof the spring members K will create an increasingly greater expansiveforce outwardly and the expansive force so created will be exerted onthe piston skirt through the parts L.

I have found that to obtain best results the piston and its expander infree or unadjusted condition should be placed in its cylinder beforeadjustment of the expander is made. When this is done, the nuts N can beturned and manipulated to expand the skirt to the proper degree andeffect a good and proper iit between the piston and the cylinder wallwith minimum effort.

If the spring members andother parts of the expander are formed as inthis embodiment the members K in each pair will cross ata point abovethe pin bosses and above the'wrist pin H and if for any reason theexpander becomes dislodged accidentally it will be prevented fromdropping into'the crank case of the engine.

As stated above I have shown herein one embodiment only of my inventionbut it should be understood that the arrangement, position, size, andshape of the various parts of the expander may be changed within widelimits in adapting my invention to expanders of various'types. Forinstance, spring metal may be substituted for the spring wire used toform the membersK in the present embodiment. This and other changes maybe made without deviating from the spirit of my invention as included inthe appended claims.

What I `claim as new and desire to secure by Letters Patent is: c

1. A piston expander comprising a pair of spring members extendingacross the hollow interior of the piston and crossing eachv other,` oneend of each of said members having a part arranged to engage the innersurface of said skirt and means joining adjacent ends of said membersfor movingl the adjacent ends of said members relative to each otherwhereby the expansive force created by said spring members and exertedby said engaging parts lagainst said skirt can be adjusted.

2. A piston expander comprising a pair of spring members extendin-gacross the hollow interior of the piston and crossing each other, Ioneend of veach `of said members having a part arranged to engage the innersurface of said skirt and means joining adjacent ends of said membersfor moving the adjacent ends of said members away from or toward eachother whereby the expansive force created by said spring members andexerted by said engaging parts against said skirt can be adjusted andsaid means being arranged to maintain said members in adjusted position.

3. A piston expander comprising a pair of spring members extendingacross the hollow interior of the piston and crossing each other, eachof said members having one end thereof anchored in the piston wall andthe free end thereof carrying a part arranged to engage the innersurface of the piston skirt, and means joining adjacent ends of saidmembers for moving the free end of one member relative to the anchoredend of the other member whereby the expansive force created by saidspring members and exerted by said parts against said skirt may beadjusted.

-4. A piston expander comprising a pair of spring members extendingacross the hollow interior of the piston and crossing each other, eachof said members having one end thereof anchored in the piston wall andthe free end thereof carrying a part arranged to engage the innersurface of the piston skirt, means joining adjacent ends of said membersfor moving the free end of one member away from or toward the anchoredend of the other member whereby therelative force created by said springmembers and exerted by said parts against said'skirt can be adjusted,and said means being arranged to maintain the ends of said members inadjusted position.

5. A piston expander comprising a pair of spring members anchored atopposed points in the wall of Va piston head and extending across thelhollow interior of said piston, one end of each of said members beingfree and carrying a part arranged to engage'the inner surface of thepiston skirt, means joining adjacent ends of said members for moving thepart carried by the free end of one member away from or toward theanchored end of the other member whereby the expansive force created bysaid spring members and exerted by said parts against said skirt can beadjusted.

6. A piston expander comp-rising a pair of spring membersA with an endof each member projecting into a suitable aperture formed in the pistonvwall whereby said ends will be xed, said members 'extending across thehollow interior of .said piston and crossing each other, the free end ofeach of said members being arranged to engage the inner surface of thepiston skirt, means joining adjacent ends of said members for moving thefree end of one member toward the fixed end of the other member wherebythe expansive force created by said spring members and exerted by saidparts against said skirt may be adjusted.

.'7.A piston expander comprising a pair of? spring members with an endof each member projecting intoa suitable aperture formed in the pistonwall whereby said ends will be fixed, said members extending across thehollow interior of said piston and crossing each other, the free end ofeach of said members carrying a part arranged toengage the inner surfaceof the piston skirt, a rod secured to the fixed end of each of saidspring g members and extending through said part carried by said freeend and means for moving said part along said rod wherebyIsaid free endof one of said spring members can be moved away from or toward the xedend of the other member and the expansive force created by said springmembers and exerted by said partsagainst said skirt can be adjusted.

8. A piston expander comprising a pair of spring members with an end ofeach member projecting into a suitable aperture formed in the pistonwall whereby said ends will be xed, said members extending in oppositedirections across the hollow interior of said piston and crossing eachother, the free end of each of said members carrying a part arranged toengage the inner surface of the piston skirt, a rod secured to the fixedend of each of said spring members and extending through said partcarried by said free end and means for moving said part along said rodwhereby said free end of one of said spring members can be moved awayfrom or toward the fixed end of the other member and the expansive foreecreated by said spring members and exerted by said parts against saidskirt can be adjusted, and means arranged to maintain said parts inadjusted position on said rods.

WALTER C. KNOEBEL.

